Java ArrayDeque contains()方法

java.util.ArrayDeque.contains(Object) 如果此双端队列包含指定的元素，则此方法返回true。

1 语法

public boolean contains(Object o) 

2 参数

o：要检查的对象是否包含在双端队列中。

3 返回值

如果此双端队列包含指定的元素，则此方法返回true，否则返回false。

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * java.util.ArrayDeque.contains(Object)方法的例子
 */
import java.util.ArrayDeque;
import java.util.Deque;

public class Demo {
    public static void main(String[] args) {

        // create an empty array deque with an initial capacity
        Deque<Integer> deque = new ArrayDeque<Integer>(8);

        // use add() method to add elements in the deque
        deque.add(20);
        deque.add(30);
        deque.add(10);
        deque.add(18);

        // let us print all the elements available in deque
        for (Integer number : deque) {
            System.out.println("Number = " + number);
        }

        // deque contains element 10
        boolean retval = deque.contains(10);

        if (retval == true) {
            System.out.println("element 10 is contained in the deque");
        } else {
            System.out.println("element 10 is not contained in the deque");
        }

        // deque does not contain element 25
        boolean retval2 = deque.contains(25);

        if (retval2 == true) {
            System.out.println("element 25 is contained in the deque");
        } else {
            System.out.println("element 25 is not contained in the deque");
        }
    }
}

输出结果为：

Number = 20
Number = 30
Number = 10
Number = 18
element 10 is contained in the deque
element 25 is not contained in the deque